The process of manufacturing ethylene oxide (EO) by oxidation of ethylene with oxygen in the vapor phase produces a product stream which is very dilute in ethylene oxide--on the order of one to two percent. The ethylene oxide is normally recovered by absorbing in water and employs a large counter-current tower for the purpose. Carbon dioxide, which is a by-product, is also absorbed from the product stream, but not as completely as the EO. The water containing the absorbed EO is then passed to a stripping column where the EO is recovered and the water recycled to the absorbing tower.
The absorption process is energy intensive, i.e., the absorbing water must be maintained at about 35.degree. C. in order to accommodate the heat load from the reactor gases and efficiently absorb the EO. Further, the temperature required to desorb the EO from the aqueous solution is about 95.degree. C. At this temperature some of the water evaporates which is a further waste of energy.
It would be highly desirable if an absorption system could be devised which would be less energy intensive and employ smaller apparatus and equipment. Thus, it has now been found that this can be accomplished by employing ethylene carbonate as the absorption medium.